"I'm encouraging my fellow brothers and sisters and my fellow Americans to donate their time, to come up and protect these soldiers that are defenseless against a threat," Robert Bolt said.

Bills have been proposed in Congress to changes the regulations to allow recruiters to carry weapons, and some states, including Indiana, have authorized National Guard members to be armed at their own facilities.

Authorities say Mohammad Abdulazeez shot up a recruiting center, wounding one, before driving to a Navy Reserve facility where he shot and killed four Marines and one sailor before being killed by police.